Nanocrystalline zinc ferrite photocatalysts formed using the colloid mill and hydrothermal technique

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 155; no. 1; pp. 534 - 541
• Main Authors: Fan, Guoli, Gu, Zhijun, Yang, Lan, Li, Feng
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.12.2009; Elsevier
• Subjects: Applied sciences; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Colloid mill; Crystallization, leaching, miscellaneous separations; Exact sciences and technology; General and physical chemistry; Nanostructure; Photo-degradation; Reactors; Synthesis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zinc ferrite; Zinc ferrite; Nanostructure; Colloid mill; Synthesis; Catalysis; Photo-degradation; Confinement; Mixing; In situ; Powder; Thermal stability; Oxidation; Reactor; Nanocrystal; Photochemical degradation; Scanning electron microscopy; Photocatalysis; X ray diffraction; Pollutant; Ultraviolet radiation; Transmission electron microscopy; Surface area; Formation mechanism; Catalyst; Colloid particle; Reflectance
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2009.08.008

Nanocrystalline zinc ferrite (ZnFe 2O 4) photocatalysts with different crystallite sizes prepared using the colloid mill and hydrothermal technique are reported. This synthetic approach involves a very rapid mixing of Fe 3+ cations with reducing agent and reduction process in a colloid mill reactor, followed by a slow oxidation of iron nuclei and structural transformation in a separate hydrothermal process. Material characterization has been presented by powder X-ray diffraction (XRD), chemical element analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra. The results indicate that ZnFe 2O 4 nanocrystals with the uniform crystallite sizes have been obtained using in situ forming iron nuclei as the source of Fe. A possible formation mechanism of ZnFe 2O 4 nanocrystals was proposed. Furthermore, through photocatalytic investigation, these ZnFe 2O 4 nanocrystals displayed better abilities to photodecompose acid orange II azodye molecule under UV irradiation due to quantum confinement effect and high surface area structure, as compared to bulk ZnFe 2O 4 sample prepared by the conventional solid-state method. Since as-synthesized ZnFe 2O 4 nanocrystals have excellent chemical and thermal stabilities and exhibit good photocatalytic activities, it can be expected that they may have potential application in the field of industrial photo-degradation of organic azodye pollutants.